I am using Deltron Clearcoat, and laquour thinner to clear some sideview mirrors.?

I part clear, 2 parts thinner. After spraying on 2 coats, i let is cure over night. But the nezt day, parts of them mirrors cured with a haze while other cured clear. What coul dbe the problem?? Anyway to fix this without sanding off clear back to basecoat?